The invention relates to the exploitation of the effects of magnetic fields on matter for industrial purposes, for applying physical and chemical reactions in a dispersed medium.
It is a particular object of the invention to provide a process which permits physical and/or chemical reactions to be facilitated, in a fluid medium and which consists essentially in subjecting to a variable magnetic field, a magnetic material in freely dispersed form in this fluid, constituted, at least at the surface, of a substance playing a physical and/or chemical role in said reaction.
The magnetic material can be in the form of particles or elements of any shape and of any size, according notably to the application contemplated and the dimensions of the container or of the reactor containing the fluid medium. These particles or elements are not necessarily constituted by a homogeneous solid substance; they may also include portions of different nature, one against the other or one within the other. In practice, this enables any substance whatever to be rendered magnetic for the process of the invention, for example by using mixtures or, preferably, by forming particles or elements enclosing a core of a common magnetic material, coated with a surface layer of a substance selected separately according to the constituents present in the medium and the role which is ascribed to it in the reaction. Materials qualified as magnetic within the scope of the invention are principally ferromagnetic materials, such as soft iron and iron ores, but also possibly strongly paramagnetic materials, the essential being that the dispersed material moves selectively within the fluid medium under the effect of the magnetic field.
The magnetic field may be created by any conventional means, in one or several directions, provided that it is possible to vary it, in intensity and/or in position or direction. Preferably sufficiently intense magnetic fields are used, with sufficiently rapid variations, to maintain the ferromagnetic material effectively in suspension in the fluid and subjecting it to accelerations substantially higher than those that it can undergo for other reasons, for example due to the force of gravity.
It is possible, in particular, to create a magnetic field, transversally with respect to gravity, by means of different electromagnetic coils arranged outside a container or reactor containing the fluid medium and the magnetic material. These coils may be at least two in number, preferably more, distributed around the receiver or reactor at the same level. The apparatus then advantageously includes control means for the supply of the coils, conventional in themselves, enabling various coils to be successively or alternately supplied with D.C. or alternating currents. It is also possible to arrange similar coils on a least two different levels of the apparatus. Preferably, the coils are then arranged by placing opposite poles above one another, in the same way as adjacent poles around the container or reactor are advantageously opposite poles. The various coils may be supplied successively in random manner or in any other periodic form.
In other cases, it may be advantageous to arrange electro-magnets successively in the path that the magnetic material follows in the absence of a magnetic field and to supply the electro-magnets cyclically one after the other so as to draw the magnetic material in reverse direction to the above path. This arrangement may be advantageous, in particular, when the magnetic material is constituted by particles in suspension in a fluid flowing continuously in a certain direction, and especially where it relates to fine particles entrained with this fluid in the form of a mud. In other cases, it is preferred on the contrary to control the supply of the electro-magnets alternately so as to cause to and from movements of the particles with respect to the path of the fluid. In addition, it is often advantageous to interrupt the magnetic field created in each direction concerned periodically, the magnetic material then being drawn, during the interruption fo the fields, by the other forces to which they may be subjected, for example by entrainment by the flow of fluid, by the rising force of the fluidized beds or by the action of gravity. However in this case as in the preceeding ones, there is every interest in preserving at least a periodic alternation between fields of opposite sense in at least neighbouring directions, or even in the same direction, preferably transverse with respect to the direction in which the resultant of the other possible forces of entrainement of the dispersed material is exerted. One thus arrives easily at realizing alternating variations of acceleration which counter any possibility of organization of the particles in a continuous flow at a constant linear speed.